thinking of getting another tumbler

Processing true "rough" benefits from the harder cutting action that rotary tumblers provide, if you have a rotary already and are looking for a second machine, you can dedicate the rotary to course cycles and use the vibe for everything beyond that, but if you already have a vibe, I'd point you to something like the QT series Lortones or bigger Thumblers.
Since coarse cycles generally take longer in the first place, as well a being the lowest yield, and a vibe cuts down the time on subsequent stages, you will want your rotary to feed a few batches through at a time to keep the vibe busy...that would be my suggestion anyway.

I've got a Lortone 33B and was thinking about getting the Thumbler 18 lb model. The Lortone won't keep up with the Thumbler. I've hundreds of lbs of obsidian I can process now and 80+ lbs of mixed agates coming from a board member here. I guess what I what to know is - what is the ONE tumbler I need to process this?

Thanks,
Lee

I also have noticed that the larger rotary tumblers seem to process faster than the smaller, and wondered why that was so. I've found that the QT12 will usually need to be recharged within 3-4 days, the QT6 in about a week, but the 33B usually needs around ten days before its grit is expended (with all running coarse). I don't measure out the grit down to the grain, of course, but I'm pretty sure I'm putting in equal amounts per load size (and the slurry is the same consistency when opened).

I concur with the idea that there is such a thing as too big as well, at least from the hobbyist standpoint. The QT-12 barrel is about as much as I ever want to have to lift and carry when fully charged, don't think I'd care to try anything larger. They also get to be grit-eating monsters at the larger sizes, I can see now why people would be looking to make 50lbs+ grit purchases. When it takes around a pound of grit to charge a barrel and it is being consumed inside a week - that's a lot of grit, real fast.

lparker - another thing that will cut down on the processing time of rough rock is a trim saw, like the Workforce (sold through Home Depot). The WF is a tile saw, but it works well on rock too. And they're useful even for people (like me) who aren't cabbing or slabbing - just trimming off the edges of rough rock makes a difference. If you aren't having to rely solely on the tumbler to smooth out all the edges or eliminate or reduce the pits or valleys, you won't have to leave the rocks in coarse nearly as long. And you also have the added benefit of getting a preview of what your rock will look like finished, on the cut faces when they're wet.

I think you are going to like the QT12. Mine feeds my 3# rollers with all the shaped rough I need and I agree the larger tumbler does a faster job roughing the material to shape.